js將radiosforEachfunctionradio 儲存前一次點擊的值 var previousValue = radiovalue; 監聽點擊事件 radioaddEventListenerclick function 檢查本次點擊的值是否與前一次點擊的值相同 if radiovalue === previousValue 恢復到初始狀態

var radios = document.querySelectorAll('input[type="radio"]');

for (var i = 0; i < radios.length; i++) { (function(radio) { var previousValue = radio.value;

radio.attachEvent('onclick', function() {
  if (radio.value === previousValue) {
    radio.checked = false;
    previousValue = null;
  } else {
    previousValue = radio.value;
  }
});

})(radios[i]); }